Light sensor arrangement for auto-darkening lenses and method

• US 20050007667A1
• Filed: 07/09/2004
• Published: 01/13/2005
• Est. Priority Date: 07/10/2003
• Status: Active Grant

• Current Assignee: Taroko International Co., Ltd.
• Original Assignee: Lightswitch Safety Systems Incorporated
• Inventors: Fergason, John D.
• Granted Patent: US 7,550,698 B2
• Time in Patent Office: Days
• US Class Current: 359/601
• CPC Class Codes: A61F 9/067 with variable transmission

Abstract

A control for an auto-darkening lens or other optical device monitors light incident on the viewing area or in relatively close proximity to the viewing area of the lens to provide accurate light sensing and to avoid inadvertent blocking of light to one or more light sensors. Reflectors, prisms, prism strips and the like may be used to direct light to the sensor(s). A method for detecting light incident on an auto-darkening lens and a method for controlling an auto-darkening lens direct light from the viewing area of an auto-darkening lens or from relatively close proximity to the viewing area to one or more sensors to detect such light and, accordingly, to control operation of the auto-darkening lens.

Claims

1. An auto-darkening lens, comprising

a controllable shutter having at least a relatively dark state and a relatively clear state,

operating circuitry to operate the controllable shutter to such states,

a sensor to sense incident electromagnetic energy, and

a light guide to receive incident electromagnetic energy in proximity to the controllable shutter to guide such electromagnetic energy to the sensor.

2. The lens of claim 1, said electromagnetic energy comprising light.

3. The lens of claim 1, said controllable shutter comprising a liquid crystal shutter.

4. The lens of claim 1, said operating circuitry including a power supply.

5. The lens of claim 1, said light guide comprising a light pipe.

6. The lens of claim 5, said light guide comprising a light inlet and a light outlet, the light inlet being in the area of the controllable shutter, and the light outlet being in the area to direct light to the sensor.

7. The lens of claim 6, said light guide comprising a solid material.

8. The lens of claim 6, said light guide comprising reflective surfaces in proximity to the light inlet and light outlet, and further comprising a light conductor for conducting light between the light inlet and the light outlet.

9. The lens of claim 6, said light guide comprising a solid light pipe.

10. The lens of claim 9, said solid light pipe comprising a plastic material.

11. The lens of claim 9, said solid light pipe comprising a polymer material.

12. The lens of claim 1, said light guide comprising a number of light directors.

13. The lens of claim 12, said light director comprising a number of sensors corresponding to the number of light directors.

14. The lens of claim 1, said light guide comprising reflectors.

15. The lens of claim 1, said light guide comprising a prism.

16. The lens of claim 15, said prisms comprising a prism strip.

17. The lens of claim 16, said prism strip being at a side of the shutter.

18. The lens of claim 17, said prism strip including a prism strip at the bottom of the shutter.

19. The lens of claim 16, said prism strip comprising a prism strip at the bottom of the shutter.

20. The lens of claim 1, said controllable shutter being positionable before the eyes of a wearer and providing a viewing window for the wearer, and the light guide having a light inlet in the area of the viewing window.

21. The lens of claim 20, said light guide having a light inlet that is in the path of light to the viewing window.

22. The lens of claim 20, wherein the light inlet is approximately in the area of the viewing window intended for a wearer'"'"'s eyes to be positioned to look through the viewing window.

23. The lens of claim 22, wherein the light inlet is approximately between the areas of the viewing window through which a wearer'"'"'s eyes would have respective views through the viewing window.

24. The lens of claim 15, said prism comprising a number of prisms cooperative to direct light to the sensor.

25. The lens of claim 22, said prism comprising a prism strip.

26. The lens of claim 25, wherein the controllable shutter provides a viewing window, and said prism strip comprising a number of prism strips, each located at a respective side of the controllable shutter adjacent the viewing window thereof to direct light to a respective sensor.

27. The lens of claim 1, wherein the sensor and operating circuitry are on a common circuit board.

28. The lens of claim 1, wherein the controllable shutter is mounted in a welding helmet.

29. The lens of claim 1, wherein the controllable shutter is a welding lens.

30. The lens of claim 1, further comprising a housing supporting the controllable shutter, and wherein at least part of the sensor and operating circuitry are in the housing.

31. The lens of claim 30, wherein the light guide directs light into the housing to the sensor.

32. A control for an auto-darkening lens that has a controllable shutter providing a viewing window, comprising

a light responsive control to control a controllable shutter, and

a light director having a light inlet positionable in a viewing window area of a controllable shutter for directing light to the light responsive control.

33. The control of claim 32, said controllable shutter having a portion through which a user may view beyond the shutter, and wherein the light inlet is in the at least approximately in the area of said portion to receive incident light at least substantially representative of incident light on the shutter in a direction toward at least an eye of such user.

34. The control of claim 32, wherein the light responsive control comprises a photosensor and operating circuitry.

35. The control of claim 32, wherein the light director comprises a light conducting solid.

36. The control of claim 32, wherein the light director comprises a light pipe.

37. The control of claim 32, wherein the light director comprises a reflecting surface.

38. The control of claim 37, wherein the light director comprises a prism.

39. The control of claim 38, wherein the light director comprises a number of prisms.

40. The control of claim 39, wherein the prisms comprise a reflecting surface to reflect light to the light responsive control and a light transmitting surface.

41. A control for an optical device that has a controllable shutter providing a viewing window, comprising

a light responsive control to control a controllable shutter, and

a light director having a light inlet within a viewing window area of such a controllable shutter for directing light to the light responsive control.

42. A control for an auto-darkening lens that has a controllable shutter providing a viewing window, comprising

a light responsive control to control a controllable shutter, and

a light director having a light inlet positionable laterally adjacent a viewing window area of a controllable shutter for directing light to the light responsive control.

43. The control of claim 42, said light director comprising a number of light directors, at least one light director positionable adjacent a viewing window at one side of such a viewing window area and at least one light director positionable adjacent the other side of such a viewing window.

44. An auto-darkening lens comprising a housing, a photosensor, a controllable shutter controllable in response to light sensed by the photosensor, and a light director for directing light from an area at least one of in a viewing window of the controllable shutter and laterally adjacent the viewing window.

45. The lens of claim 44, said light director comprising a light pipe.

46. The lens of claim 45, wherein said light pipe has an inlet located in the viewing window.

47. The lens of claim 44, said light director comprising a light reflector.

48. The lens of claim 47, said light reflector being in the area of the viewing window.

49. The lens of claim 47, said light reflector having a planar face.

50. The lens of claim 47, said light reflector having a convex curved reflective surface.

51. The lens of claim 50, said convex curved reflective surface being positioned to receive incident light directed toward the viewing window over a relatively wide acceptance angle and to direct such light along a path toward the photosensor.

52. The lens of claim 51, said light director comprising a light directing device and a collecting lens to tend to limit the amount of ambient light that is directed to the photosensor.

53. The lens of claim 52, said light directing device comprising a reflector and said collecting lens comprising a plano-convex lens.

54. The lens of claim 44, said light director comprising a light directing device and a collecting lens to tend to limit the amount of ambient light that is directed to the photosensor.

55. The lens of claim 54, said light directing device comprising a reflector and said collecting lens comprising a piano-convex lens.

56. The lens of claim 51, said light director further comprising an aperture to tend to limit the amount acceptance angle for light to the light director to limit acceptance angle for light that is directed to the photosensor.

57. The lens of claim 44, said light director comprising a prism adjacent the viewing window.

58. The lens of claim 44, said light director comprising a prism on each lateral side of the viewing window.

59. The lens of claim 48, each of said prisms comprising a prism strip.

60. The lens of claim 59, wherein each prism strip includes a number of prisms.

61. The lens of claim 60, wherein a number of prisms in a prism strip include a light reflecting surface to reflect light that is incident thereon toward the sensor and a generally light transmitting surface for transmitting at least some light reflected from one toward the sensor.

62. A method of controlling an auto-darkening light shutter, which provides a viewing window, comprising detecting light incident on the viewing window in the area of the viewing window.

63. The method of claim 62, detecting light incident on the shutter comprising using a light pipe to direct light from the area of the viewing window to a sensor.

64. A method of controlling an auto-darkening shutter that provides a viewing window, comprising directing light from both lateral sides of the viewing window to a photosensitive control as a representation of light incident on the viewing window thereby to control operation of the auto-darkening shutter.

65. The method of claim 64, said directing light comprising using prism strips.

66. The method of claim 64, said directing light comprising directing light from one lateral side of the viewing window to one photosensor and light from the other lateral side of the viewing window to a different photosensor;

and using control circuitry responsive to the respective photosensors to control operation of the controllable shutter.

67. A method of controlling a light shutter that provides a viewing window, comprising directing light from at least partly within the viewing window to a photosensitive control as a representation of light incident on the viewing window thereby to control operation of the shutter.